Controlling microbial growth in noncarbonated dilute juice beverages is an ongoing concern among beverage manufacturers. Such beverage products, when exposed to food spoilage microorganisms, provide an excellent environment for rapid microbial growth. Such exposure can, and infrequently does, result from accidental inoculation of the beverage products during manufacturing or packaging. Food spoilage microorganisms can then rapidly proliferate by feeding on nutrients provided by the fruit juice component of the noncarbonated dilute juice beverages.
Of course, microbial proliferation in noncarbonated dilute juice beverages will not occur without the requisite product exposure to yeast or bacteria. Manufacturing and packaging operations directed to the prevention of such exposure is preferred, but provisions are often made for any infrequent accidental exposure to the isolated beverage product. Such provisions are directed to limiting or preventing subsequent microbial proliferation to thus limit or prevent food spoilage.
Subsequent microbial proliferation in noncarbonated dilute juice beverages can be controlled to some extent by maintaining the beverages in cold storage, e.g., less than about 10.degree. C. Microbial proliferation in noncarbonated dilute juice beverages can also be controlled or limited to some extent by manufacturing and storing the beverages as frozen concentrates. Microbial proliferation is further inhibited in frozen concentrates by even lower storage temperatures and by reduced water activity in the concentrate. However, whether refrigerated as a noncarbonated dilute juice beverage or stored as a frozen concentrate, such beverages still require cold storage which is much more expensive than storage under ambient conditions. Moreover, there is limited cold storage space in retail stores in which such noncarbonated dilute juice beverages or frozen concentrates can be stored.
Beverage products which can be maintained under ambient conditions, e.g. at about 20.degree. C., are more preferred than chilled beverages or frozen concentrates from a storage cost standpoint. However, ambient temperatures promote subsequent microbial proliferation in noncarbonated dilute juice beverages.
Beverage products can be maintained under ambient conditions provided that such beverages are heat pasteurized during packaging (hot packing) or are packaged under completely aseptic conditions (aseptic packaging). Hot packing involves pasteurization of the beverage and its container such that the resulting sealed beverage product contains no food spoilage microorganism. Likewise, packaging under completely aseptic conditions will produce a beverage product completely free of food spoilage microorganisms. Accordingly, these beverage products can be stored under ambient conditions since there are assuredly no food spoilage microorganisms therein to feed on the beverage nutrients and rapidly proliferate.
Aseptic packaging methods, however, are often unsuitable for manufacturing beverages products packaged in certain beverage containers, e.g., rigid containers such as glass and cans. An aseptic or sterile environment is difficult to maintain during aseptic packaging operations. Frequent cleaning of the packaging line is necessary which is time consuming, expensive and is too frequently ineffective in preventing microbial contamination.
Hot packing methods are likewise unsuitable for manufacturing certain types of beverage products. This well known method involves heat pasteurization of the juice beverage during packaging at temperatures of between about 85.degree.-105.degree. C. This method is commonly utilized in the manufacture of canned or bottled (glass) beverages. However, not all beverage containers can withstand heat-pasteurization during packaging. For example, flexible containers made from high density polyethylene, which have become more popular with consumers, should not be subjected to the pasteurization temperatures utilized during hot packing operations.
Preservatives have been used in noncarbonated dilute juice beverages to provide some degree of microbial inhibition. Preservatives commonly used in beverage products include, for example, sorbates, benzoates, organic acids, and combinations thereof. However, such preservatives often contribute an off-flavor to the beverage products when used at the levels necessary to inhibit subsequent microbial proliferation at ambient temperatures. Moreover, when used at concentrations sufficiently low to avoid off-flavor development, such preservatives have heretofore been unable to effectively inhibit the growth of many preservative resistant spoilage microorganisms.
Accordingly, most noncarbonated dilute juice beverages are hot packed in cans or glass bottles, aseptically packaged, or they are maintained in cold storage until consumed.
The foregoing considerations involving the effective inhibition of subsequent microbial proliferation in noncarbonated dilute juice beverage products indicates that there is a continuing need to identify noncarbonated dilute juice beverage products that can be manufactured without the use of hot packing or aseptic packing operations, and that can be stored at ambient temperatures without the use of excessive concentrations of preservatives. Accordingly, it is an object of the present invention to provide such noncarbonated dilute juice beverage products and processes for preparing them, and further to provide such beverage products which can be maintained at ambient temperatures for at least about 10 days, preferably for at least about 20 days, without substantial microbial proliferation therein.